Worldwide breast cancer is the second most common type of cancer and one of the most common causes of cancer death in humans. It is the most common cancer in women and makes up a third of cancer occurrence of women in the US. Common tests that provide information to assists in the diagnosis or prognosis of breast cancer include mammograms and tissue biopsy followed by combinations of histological examination, immune-histochemical detection with antibodies to estrogen receptor (ER), progesterone receptor (PR) and/or HER2/neu proteins.
Current treatment of breast cancer includes surgery, chemotherapy, radiation therapy and immunotherapy. Targeted therapy such as HER2/neu antibody first became available in the late 1990's. Other targeted therapies involve either blocking estrogen or the estrogen receptor. Estrogen is implicated in initiation and progression of breast cancer growth. Progesterone therapy is often used to block estrogen. Estrogen receptor antagonists such as tamoxifen and raloxifene have been used to treat breast cancer. Research shows that Tamoxifen becomes ineffective in 35% of patients taking the drug particularly where the breast cancer has metastasized.
Metastasis is a complex series of steps in which neoplasic cells leave the original tumor site and migrate to other parts of the body via the blood stream or the lymphatic system and start new tumors that resemble the primary tumor. Breast cancer cells are often transported through the lymphatic pathway to bone or other areas such as liver, lung or brain. It may be life saving to predict whether a primary cancer has the potential to metastasize such that high risk patients can be subject to closer follow up or specific treatment regime that will vary where the cancer has metastasized. Currently there is no way to visualize metastatic tumors so that effectiveness of therapy can be more easily monitored. Currently, detection of metastatic sites requires numerous, time consuming and costly tests that does not have very high specificity.
Transient receptor potential cation channel subfamily V member 4 TRPV4 is a protein that in humans is encoded by the TRPV4 gene. The TRPV4 protein is a member of the OSM9-like transient receptor potential channel (OTRPC) subfamily in the transient receptor portential (TRP) superfamily of ion channels. The encoded protein is a Ca2+-permeable, nonselective cation channel that is thought to be involved in the regulation of systemic osmotic pressure.